Abstract

Regression ra tes of a hypergolic combination of fuel and oxidiser have been experimentally measured as a function of chamber pressure, mass flux and the percentage component of the hypergolic compound in natural rubber. The hypergolic compound used is difurfurylidene cyclohexanone (DFCH)
which is hypergolic with the oxidiser red fuming nitric acid (RFNA) with ignition dela y of 60-70 ms. The
data of weight loss versus time is obtained for burn times varying between 5 and 20 seconds. Two methods of correlating the data using mass flux of oxidiser and the total flux of hot gases have shown that index n of
the regression law r=aGoxn or r=aGnxn-1 (x the axial distance) is about 0.5 or a little lower and not
0.8 even though the flow through the port is turbulent. It is argued that the reduction of index n is due to
heterogeneous reaction between the liquid oxidiser and the hypergolic fuel component on the surface.